* Add signed refund
* Use signed 256-bit integer for sstore gas refund substate
* Fix tests
* Remove signed mod and use i128 directly
* Fix evm test case casting
* Fix jsontests ext signature
* Implement CREATE2 gas changes and fix some potential overflowing
* Ignore create2 state tests
* Split CREATE and CREATE2 in gasometer
* Generalize rounding (x + 31) / 32 to to_word_size
* Implement last_checkpoint_storage_at
* Add reverted_storage_at for externalities
* sstore_clears_count -> sstore_clears_refund
* Implement eip1283 for evm
* Add eip1283Transition params
* evm: fix tests
* jsontests: fix test
* Return checkpoint index when creating
* Comply with spec Version II
* Fix docs
* Fix jsontests feature compile
* Address grumbles
* Fix no-checkpoint-entry case
* Remove unnecessary expect
* Add test for State::checkpoint_storage_at
* Add executive level test for eip1283
* Hard-code transaction_checkpoint_index to 0
* Fix jsontests
* Add tests for checkpoint discard/revert
* Require checkpoint to be empty for kill_account and commit
* Get code coverage
* Use saturating_add/saturating_sub
* Fix issues in insert_cache
* Clear the state again
* Fix original_storage_at
* Early return for empty RLP trie storage
* Update comments
* Fix borrow_mut issue
* Simplify checkpoint_storage_at if branches
* Better commenting for gas handling code
* Address naming grumbles
* More tests
* Fix an issue in overwrite_with
* Add another test
* Fix comment
* Remove unnecessary bracket
* Move orig to inner if
* Remove test coverage for this PR
* Add tests for executive original value
* Add warn! for an unreachable cause
* Comply EIP-86 with the new CREATE2 opcode
* Fix rpc compile
* Fix interpreter CREATE/CREATE2 stack pop difference
* Add unreachable! to fix compile
* Fix instruction_info
* Fix gas check due to new stack item
* Add new tests in executive
* Fix have_create2 comment
* Remove all unused references of eip86_transition and block_number
* Implement EIP-1052 and fix several issues related to account cache
* Fix jsontests
* Merge two matches together
* Avoid making unnecessary Arc<Vec>
* Address grumbles
* Add a basic instruction c-like enum
* Fix all compiling errors
* Fix tests
* Access instruction info as a Instruction impl
* Use macro to avoid duplication in from_u8
* Use single space instead of multiple tabs to avoid formatting issue
* Fix evmbin compile
* typo: indentation
* Use if let to remove an expect
* Address grumbles
* Update `add_license` script
* run script
* add `remove duplicate lines script` and run it
* Revert changes `English spaces`
* strip whitespaces
* Revert `GPL` in files with `apache/mit license`
* don't append `gpl license` in files with other lic
* Don't append `gpl header` in files with other lic.
* re-ran script
* include c and cpp files too
* remove duplicate header
* rebase nit
